Method of and apparatus for electric welding



" cal connections so that the the work is posi- Patented Sept. 21, 1926.

UNITED sTArEs PATENT OFFICE:

WINSTON I. STOODY, OIZWHITTIEB, CALIFORNIA, ASSIGNOR TO STOODY COMPANY,OI

WHITTIER, CALIFORNIA, A CORPORATION OF CALIFORNIA. I

METHOD OF AND APPARATUS FOR ELECTRIC WELDING.

Io Drawing. Continuation of application Serial No. 77,388, filedDecember 28, 1925. This application filed August 19, 1926. Serial No.180,339.

'This invention relates to improvements in the method of and apparatusfor electric welding.

This application is a continuation of my co-pending patent applicationSerial No. 77,388, filed December 23, 1925, and allowed August 5, 1926.

It is the object of my present invention to improve the method of andapparatus for electric welding with ferrous electrodes having arelatively low carbon content, such as those commonly referred to asiron, mild steel, or medium steel; to improve'thc quality of the weld;to make it easier to produce uniformly good welds; to getbetterpenetration; to increase the rate of deposit; to lessen theconsumption of electric energy required to produce a given deposit; toavoid the s0 called wild arc; to decrease spatt-eringyto get greaterdensity and homogeneity of the deposited metal; to avoid pinholes; andas a result of these things to make it possible to weld more efiicientlyand to obtain better results and greater economy.

Mostof the welding rods 'or welding electrodes used in electric weldingare of ferrous metal of low carbon contentthe so-called iron, mildsteel, or medium steel welding rod. By the term low carbon I mean acarbon content of not more than about 0.35%. Such low-carbon weldingrods are used for probably 80% or more of all elec-- tric weldingoperations.

Heretofore, in the use of low-carbon welding rods for direct-currentelectric welding,-

it has been found necessary, in order to produce a satisfactory weld, tomake theelectri- T1118 is tive and the electrode negative. usuallyreferred to as straight folarity, Straight polarity has been consi crednec- "essary, and has been actually nry with the low-carbon electrodesused, in order to get a satisfactory deposit of welding metal with astead arc and good penetration. These things ave'made and still makedirent-current electric welding impractical the ordinary electrode oflow cTrbon itself is called gum, is

Yet it has been known that indirect-current electric welding reversedpolarity gives better results than straight polarity with certain othertypes of electrodes, such as high-carbon steel electrodes, and manganese steel electrodes, and other special alloy steel electrodes, aswell as when the electrode is of non-ferrous metal. Because of therequirements mentioned above, however, it has heretofore beenimpractical to use reversed polarity with ferrous electrodes of lowcarbon contentwhich electrodes constitute most of those used in electricwelding.

I have discovered how reversed polarity may be used with ferrouselectrodesof low carbon content; and how the advantages outlined abovemay thus be obtained with that type of electrode; and my presentinvention is based on that discovery:

, In my investigation of the subject of direct-current electric welding,I have found that if such welding rod or electrode is sub stantiallyfree from lime, or from calcium in any form, it is possible to use thatelectrode successfully and advantageously with reversed polarity; butthat if lime, or calcium in any form, is present even in uite minutequantities, it somehow inter eres with the action if reversed polarityis used, and makes straightpolarity necessary for good results. 7 7

Therefore, my invention'involves directcurrent electric welding withreversed polarity, with a ferrous electrode of low carbon content andsubstantially free from lime or calcium.

This involves apparatus for electric-welding, as will appear from theclaims.

In he ordinary manufacture of ferrous welding rods, the material orstock, which ickled in dilute with water to then or sulphuric acid isthen was remove the sulphuric ac1d,i1s

both the method of and the washed with calcium hydroxide or milk of limeand usually baked, and is then drawn to wire of suitable diameter andout into welding rods of suitable length. The lime serves two importantpurposes: One is to neutralize any acid remaining on the rod; and theother is toserve as a lubricant for the rod as it passes through thewiredrawing dies. If the material is of lowcarbon content, at least someof this lime remains on and in the surface of the rod throughout thewhole series of drawing operations, and all other treatments to whichthe wire is subjected, and still persists in the final wire; although ifthe wire is of high carbon content or is of some alloy steel, I havefound that much or all of the lime is often removed in the drawing andstraightening operations. My experiments show that it is the persistentpresence of this lime on the surface of the ordinary ferrous welding rodof low carbon content that has made the straight polarity necessary withthat type of electrode. I

, The presence-of this lime in or on such ferrous electrodes of lowcarbon content may be avoided either by removing the lime from thesurface of the welding rod, or by avoiding the use of lime in the makingof the welding rod.

Thus, for example: The ordinary welding rod of low carbon content, whichhas lime adhering to it after it is delivered from the straighteningmachine, can be scraped, .pol-

' ished, or ground to remove its outside coating or outside surface, andthus to remove such adhering and embedded lime. Or, the rod, after.having been pickled in acid, washed, and treated with lime, can have thelime removed, as by washing or pickling, and then be run through thefinishing dies without lime.

I have found it very effective to avoid altogether the 'use of lime inthemanufacture of the welding rod. This may be done by making the rod orwire (from which the welding rodsare cut) with the well-knownliquor-bright finish; which usually involves passing the stock throughor dipping it in. a solution of copper sulphate or of a mixture ofcopper and tin sulphates, and then draw- 1ng wire from the stock. Thecopper, and the tin if present in the solution, plate out on the stockto some extent, and serve quite effectively as a lubricant in thesubsequent drawing of the wire; and they also act to retard subsequentcorrosion. .I have found that this liquor-bright finish, produced'onwelding rod in its manufacture without the use of any lime, givesexcellent results when the welding rod is used as a positive electrode.

By the use as a positive electrode of a ferrous weldin rod'of low carboncontentand free from lime, good welding may be obtained more easily andwith greater uniformity, and the weld or material built upon the work isusually found to be more dense and more homogeneous and to besubstantially free from pin holes such as so frequently occur in weldingwith straight polarity. Further, by this use of this welding rod, anywild arc is practically completel avoided, so that the welding materialis eposited with materially less popping and spattering. Further, it isfound that thewelding can be done more rapidly-and more economically,because there is a greater flow down of the metal for a given powerconsumption than is the case with the ordinary welding rod used as anegative electrode, and because a given weld'may thus be produced withless energy. In addition, the welding metal is deposited with betterpenetration than is the case with the ordinary lime-containing weldingrod of low carbon content used asa negative electrode. In short, theobjects set forth at the beginning are accomplished.

I am awarethat in acetylene welding it is not new to use welding rodshaving a low carbon content and comparatively free from lime; but inacetylene welding the matters of polarity and flow of current, and ofmaintaining an are, are not involved. I am also aware that indirect-current welding it is not new to use as a ositive electrode aferrous welding rod of igh carbon content, or a, non-ferrous electrode.However, so far as I am aware, it has never heretofore been feasible toweld effectively with a ferrous electrode of low carbon content used asa positive electrode; and by my invention such welding is not only madepossible but is made distinctly advanta eous over the ordi nary weldingwith straigdit polarity.

I'claim as my invention 1 Theiinprovement in the art of directcurrentelectric welding, which consistsin making the work the negativeelectrode, and usin as the positive electrode a ferrous wel ing rodwhich has a low carbon content and is suhitlantialy free from lime.

2. The 1 provement in the art of directcurrent electric welding, whichconsists in making the work the negative electrode, and usin as thepositive electrode a ferrous wel ing rod which has a low carbon contentand has a liquor-bright finish.

3. Direct-current electric welding apparatus, consisting of the work towhich the weld is to be ap lied, an electrode which is of ferrous metaof low carbon content and substantially free from lime, and electricalconnections whereby the work is made the ne tive and the electrode thepositive in t e welding operation.

4. Direct-current electric weldin a paratus, consisting of the work fb-flv hic the weld'is to be applied, an electrode which is of ferrousmetal of'low carbon content-and has a liquor-bright finish, andelectrical connections whereby the work is made the negative and theelectrode the positive in the welding operation.

5. A positive sire-welding ferrous electrode of low carbon content andsubstantially free from lime.

6. A positive arc-welding ferrous electrode of low carbon. content andhas a liquorbright finish.

In witness whereof, -I have hereunto set my hand at Detroit, Michigan,this 16th day of August, A. D. one thousand nine hundred and twenty six.

WINSTON F. STOODY.

